1. Field of the Invention
The present invention relates to an optical fiber amplifier and, more particularly, to a compact optical fiber amplifier, which can minimize the size of an optical module and increase the degree of freedom in mounting the module on a board.
2. Description of the Related Art
At present, an optical communication system which is configured to perform signal transmission between devices located in remote locations using optical signals has been widely spread and used. Moreover, the use of an optical fiber amplifier, which is configured to amplify an optical signal as it is without converting the optical signal into an electrical signal, also increases dramatically. The optical fiber amplifier employs an erbium-doped fiber, for example, as an optical amplifying means.
FIG. 1 is a schematic diagram showing the configuration of a conventional optical fiber amplifier module M employing an optical amplification optical fiber.
In the figure, the optical fiber amplifier module M comprises an optical element block 1 composed of at least one optical element constituting an optical fiber amplifier, an optical fiber block 2 composed of a connection optical fiber 21 for optically interconnecting the optical elements provided in the optical element block 1 and an optical amplification optical fiber 22, and a control block 3 for controlling the overall operation of the optical fiber amplifier. Moreover, an optical input port IP for introducing an external light into the optical fiber module M and an optical output port OP for outputting an amplified light from the optical fiber module M are provided on the outside of the optical fiber module M.
The above-described optical fiber module M is mounted on a board together with other modules in a communication system to provide the function of amplifying an optical signal transmitted and received through the communication system.
However, recently, as the reduction in size and weight of the communication systems or devices has rapidly proceeded, the size of the board detachably inserted into the communication system, for example, in the form of a card is also gradually reduced. Accordingly, the reduction in size of the module or device mounted on the board is also required.
FIG. 2 is a plan view showing an example of the configuration of a board employed in an optical communication system or device.
In FIG. 2, reference numeral A is a board detachably connected to a communication device, for example, in the form of a card. An optical fiber amplifier module M and other communication modules B, C, D, E and F are disposed on the board A. Here, the communication modules may include a power module, a transceiver module, a control module, etc. As mentioned above, with the reduction in size and weight of the communication devices, the size of the board mounted on the device is also reduced. As shown in FIG. 2, when the communication modules B, C, D, E and F are disposed on the downsized board, there is no enough space on the board, and thus the space in which the optical fiber amplifier module M is to be installed is not sufficient. For reference, the optical fiber amplifier module M shown in FIG. 2 has a size corresponding to that of an actual board A of a conventional standardized optical fiber amplifier module.
To solve the above-described problems, it is necessary to minimize the size of the optical fiber amplifier module M and mount the downsized optical fiber amplifier module M in the space on the board A. As described with reference to FIG. 1, the optical fiber amplifier module M is provided with the optical fiber block 2 as well as the optical element block 1 and the control block 3. The connection optical fiber 21 and the optical amplification optical fiber 22, which constitute the optical fiber block 2, are configured to be wound to minimize the installation space thereof. Here, when the optical fibers are wound, it is necessary to maintain the radius of curvature of the optical fibers above a predetermined level so as to prevent the transmission loss of the optical signal transmitted through the corresponding optical fiber. Therefore, it is very difficult to reduce the size of the optical fiber amplifier module M below a predetermined size.
For these reasons, the size of the optical fiber amplifier module M should be maintained above a predetermined size, and thus the size of the board A on which the optical fiber amplifier module M is mounted should also be maintained above a predetermined size, which poses a significant obstacle to reducing the size of the optical communication system or device.